A. Lange & Söhne

PeterCDE
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Did you know.... Lange could split hairs?

Dear enthusiasts,

there´s a multitude of interesting details around A. Lange & Söhne and their watches; anecdotal, historical, casual and even some small ones.
Bear with me it´s sometimes the latter to fascinate me

A detail we all appreciate are the fine engravings on a Lange watch, of which all are perfect and a very fine execution.
They are different, in shape, lettering and size; most of them aren´t that deep, but clearly visible and always nicely outlined in gold. But across the models, each watch is engraved the same way as it´s brethren of the same model.


1815 "Cuvette"

While it´s a small detail (but one that tells a bit about the brand), these engravings require a bit more of efforts than easily apparent.

First of all, these engravings are manufactured with a dedicated machine.
Lange employs a state-of-the-art computer-controlled milling machine especially produced for nano-precision milling at very small scales. To be exact, it´s a very special machine by Kern, one of the first adresses when it comes to such tools, and it looks a bit like this unit:


(image by Kern Microtechnic)

Actually the machine can do a lot more than engravings only and it does so with utter precision. To put this in some relation, it´s accurate enough to drill exactly defined holes in a human hair!
Now doing such certainly would be a remarkable task and in fact, it´s not even impossible to do so! The tiny size of the milling tools required for such is not an obstacle; it´s more the proper fixing of a human hair in the machine for processing, as soon as the milling tool touches the hair. And while some tasks at Lange require a precision well beyond the diameter of a human hair, to have maximum precision in small scales requires to think big - one of these machines is easily 7 tons in weight!


Double Split

Tiny scales need to be mastered to result in a Lange-quality engraving, which can be seen by the size of the milling tools.
While the engravings of the Lange 1´s 3/4-bridge are fairly larger, all these are made with a milling bit which measures only 3/100 (0.03) of a mm. And the engravings of a Datograph require a tool of only 0.015mm in diameter.
Each letter or numeral of the workpiece is milled several times in different directions, in order to achieve a particularly fine result and sharp edges.
You get the idea: the machine works it´s way through the metal back and forth several times, to achieve an engraving of 0.10mm depth in first instance (which will shrink to 4-5/100 of a mm once the plate or bridge is finished and decorated).


Double Split

While one may suspect it´s all in the machine, time is a vital factor.

Despite common belief such CNC technology is not capable of producing high quantites, but high qualities only.
To give it a figure, the engravings on a Lange 1 plate require 15 minutes of processing time in the machine, which thus can do 4 plates per hour or 32 plates in an 8-hour work shift. Given 220 days at work per year, the machine is fully exhausted doing 6.400 mainplate engravings.... And that´s just the engraving.
The processing time de facto is significantly smaller, for a simple reason:
All Lange bridges are German Silver, which is a relatively hard material to work on. The machines and tools don´t like it
This results in considerable wear of the toolings. All engraving tools needs to be replaced every 100 engravings at best and each of them is at least 30 Euro at costs.
The wear of the tools considerably slows down the output totals; every time a new bit is installed, of course the machine needs to be adjusted and lined up again.
To sum it up, you may get the idea creating these engravings is not a job done very fast or very cheap.

And all this doesn´t count in these highly specialized machines aren´t for free; a basic Kern can be had for 170.000 Euro, but easily be 300.000 Euro - without any special tools needed and not including the necessary programming to make it work. And of course, not including the guys who run and service them!

Putting all together, the Kern machine is more or less exclusively used to engrave all Lange movements. And the brand for sure spends a lot of efforts on doing so in a particularly nice way, which includes considerable costs at production level.
To maintain an equal "look" for all Lange watches that leave the manufacture is quite a bit more efforts than one may guess. But it wouldn´t be Lange if the brand would be happy with less

To clearify: the engravings above refer to the inscriptions only, but not the decorative engravings on the balance cock.
These are made by hand of course.

Personally i found the seemingly little details quite telling and i do hope you didn´t mind some ramblings about them

Greetings from Germany,

Peter